Question: Assume this original statement below is true: If it is Thanksgiving, then I will have a big dinner. Choose the statement that must also be true logically:
Solution: Only the contrapositive of the original statement must be true. Find the contrapositive. In other words, find the statement that reverses and negates both the hypothesis and conclusion. In this case, the contrapositive is "If I did not have a big dinner, then it is not Thanksgiving."